The invention relates to control valve assemblies for hydraulic or pneumatic actuators. It relates, more particularly, to control valve assemblies incorporating a pair of identical valves for controlling the admission of pressurized fluid to the actuator, and the discharge of fluid from the actuator, respectively, through the operation of an operator mechanism including a rocking beam.
The field of hydraulic positioning and control circuits is broad and the prior art includes many devices for controlling fluid-powered actuators by means of a pair of valves. Such valve assemblies of the prior art, while suitable for a wide range of control applications, fail to exhibit some highly desirable characteristics; the most prominent of which are:
The use of identical, separately replaceable control valves for the fluid admission and discharge functions;
The use of a common manifold for mounting these valves and for providing interconnection with the controlled actuator;
The use of single tappet (piston) means of sealing and providing additional closure forces within the valve proportional to fluid pressures.
The provision of operating means which selectively and unambiguously provide for the individual actuation of one of the two valves in the assembly, and also provide for a definite neutral position in which both valves are closed; and
The provision of internal sound suppression means within the individual valves.
It is, therefore, the primary object of the invention to provide a control valve assembly for fluid-powered actuators which utilize individual and identical supply and discharge valves mounted to a common hydraulic manifold.
It is additional object of the invention to provide a fluid control valve assembly in which the paired control valves are operated by means of a rocking beam acting on protruding tappets in each valve.
It is also an object of the invention to provide control valves in which integral sound-supression means are incorporated, in the form of serrated washers concentric with the valve stem.
It is yet another object of the invention to provide a control valve assembly which is economical in construction, reliable in operation, and simple to repair, inherently free from operator abuse, due to the fact that closure forces are mechanically determined.